Temperature control unit



June 23, 1942. J. E. woons 2,287,451

TEMPERATURE CONTROL UNIT Filed Feb. 27. 1940 Patented June 23, 1942 TEMPERATQRE CONTROL UNIT John E. Woods, Brookline, Masa, asslgnor to Clifford Manufacturing 00., Boston, Mass., a corporation of Delaware Application February 27 1940, Serial No. 321,037

2 Claims. (Cl. 200-140) The present invention relates to temperature control units, and is more particularly concerned with units of this character designed for the control of cooking ovens and similar controlled regions.

It is the purpose and object of the invention to provide a. relatively economical and compact unit of the self-contained type, which is designed for mounting directly upon the side, top or door of a portable oven or similar cooking receptacle in a manner to control the temperature of the oven through the regulation of a heating memher controlled through a switch or valve forming to the'neck 22 and the head 32, respectively, and the bond connecting the outer peripheries of the two diaphragms together. In addition the interior of the bulb and diaphragm assembly is sealed by a pin 42 drifted within the hollow bore of the head 32 and sealed by a solder bond at 31.

In actual practice such a system is completely filled with a substance which remains liquid throughout the temperature range of the apparatus from 250 to 550 approximately. Such a liquid may be one of the diphenyl compounds or mixtures of such compounds. After exhausting and filling the complete unit interiorly, the opening in the head is sealed through the tapered pin 2 by driving the pin 42 and sealing the outer end with a solder bond.

If the diaphragm members are formed from 4 Monel and the remaining portions of the unit of opening in a position to reflect the temperature within the oven. The unit is provided with a generally cup-shaped housing l5, to which is rigidly connected a supporting plate It secured to the.

housing through the rivet l1, and having a raised central portion ll spaced away from the attaching portion of the plate by an annular shoulder 20. The central portion of the plate is drawn outwardly at 22 to form an integral supporting boss or neck, upon the outer end of which are mounted nested diaphragms 24. As will be evident to those skilled in the art, the diaphragms have the form of a shallow cup, and are connected at the outer peripheral margins of the cup by soldering, brazing or welding indicated at 28.- The diaphragms are attached to the projecting neck 22 at their inner peripheries by a solder or welded bond indicated at 3|]. The central portion of the outer diaphragm is provided with a head 32 provided with an enlargement at 34 for attachment to the switch mechanism.

The bulb I as indicated may take the form of an arched disk 26 with a peripheral flange 38 seated within and connected to the plate ii at the raised central portion through a soldered or welded bond 40.

. It will be noted from the foregoing description that there are four silver solder joints, that 7 connecting the arched plate H to the support,

steel or the like, I have 'found that all of the joints may be formed simultaneously by assembling the parts of the unit wtih rings of silver solder properly arranged in the location to be occupied, thereafter subjecting the entire unit to an oven temperature sufilcient to cause flow of the silver solder in a manner to seal the joints. It will be noted from an examination of the unit that with the joints as designed and by standing the unit on end resting upon the head 32, elevation of the entire unit to the melting point of the silver solder will cause the solder to properly flow by gravity into all of the connecting joints simultaneously. By this I mean the joint connecting the arched bulb to the support, the joint connecting the inner periphery of one diaphragm to the neck, the joint connecting the inner periphery of the second diaphragm to the head 32, and finally the joint connecting the outer peripheries of the two diaphragms together. The silver solder employed in sealing the pin 42 may be handled as a separate operation. At this temperature the Monel metal of which the diaphragms are constructed will not be annealed in a manner to interfere with 'its effectiveness as 'a diaphragm.

The complete thermostatic unit may be formed, filled and sealed before assembly of the supporting plate It with the housing. Thereafter this unit may be assembled within the housing and connected to the switch mechanism to be hereinafter described.

The cup-shaped housing, as previously described, is secured directly to the wall of the oven or the like, and this housing carries at its outer end a threaded stem ll, having an adthe nested diaphragms at their inner margins lusting knob 42 mounted upon the outer end for regulation of the temperature control. The threaded stem rotates within a threaded head 44 secured to the housing, and is connected at its inner end through a. head 46 with a normally stationary but adjustable contact member 48. This contact member is provided with a contact point 49, and is anchored at its opposite end in an insulating base 50.

As will be noted, the contact comprises generally a resilient strip of conducting material engaged by the adjusting stem substantial y midway between its ends and movable the. eby to vary the normal position of the contact mem-- ber 49.

The movable or actuator contact comprises a similar resilient strip 52 anchored in the base 50 and having a-contact terminal 53. This mov able contact is provided with an opening 54 which permits the threaded stem to loosely pass. therethrough without interference with the contact, and is connected with the diaphragm head 32 through a connecting member shown best in Fig. 2. This connecting member has generally a tapered central portion 56 with two spaced connecting arms 58 joined at their outer free ends to opposite sides of the contact 52, as shown at 60. At the opposite end the head is provided with resilient inwardly tapered fingers 62 which are pressed over the enlargement 34 upon the head and locked therewith to cause the connector and the contact to move with the head. A loading spring of conical 'form indicated at $4 is interposed between a shoulder upon the head and a fixed partition 66, this loading spring acting against the expansion of the diaphragm under the influence of the liquid. With this construction it will be observed that expansion of the diaphragm due to rising temperature moves the contact 52 away from the fixed contact to open the circuit. Regulation of v the temperature at which the opening takes place may be accomplished by movement of the threaded stem and adjustment of the fixed contact 48 toward. and away from the movable contact. Leads 68 and serve to conduct current to the anchored ends of the contacts respectively.

From the foregoing description it will be observed that the entire unit is housed within the shell l5, and may be attached as a unit to the wall. cover or appropriate part of a portable or stationary oven. Generally speaking, the, circuit offset indented portion in its face and forming a centrally disposed offset hollow support terminating in a free edge indented at its outermost portion, an arched disk having a depending flange seated in said indented portion in said face in bonded relation therewith, a diaphragm assembly comprising a relatively fixed and a relatively movable diaphragm each provided with inner and outer free ends, the inner end of said relatively fixed diaphragm being seated in the indented portion in the free edge of said hollow support in bonded relation therewith, a head portion reduced at one end thereof to provide a shoulder, the inner end of the relatively movable diaphragm being seated on the shoulder of said head portion in. bonded relation therewith, the outer free ends of said diaphragms being turned back upon themselves in a direction toward said disk to provide an indented portion, said outer free ends of the said diaphragms being bonded together at said indented portion, said arch disk leads controlled by the contact members 49'and 53 connect with an appropriate relay. which would in turn-operate the main oven'switch.

What is claimed is:

1. A temperature control unit designed for attachment tothe wall of an oven or the like, comprising a supporting plate connected to the wall of theoven about an opening formed therein, said supporting plate being provided with an her, switch mechanism including a movable contact connected with and operated by the movement of said head, an adjustable fixed contact, and a manually operated knob for positionally setting the adjustable contact for the control of selected temperatures.

2. In a temperature control unit designed for attachment to the wall of an oven or'the like wherein switch mechanism is operated in response to temperature changes within theoven, a supporting plate connected to the wall of the oven about an opening formed therein, said supporting plate being provided with an offset indented portion in its face and forming a centrally disposed ofi'set hollow support terminating in a free edge indented atits outermost portion, an arched disk having a depending flange seated in said indented portion in said face in bonded relation therewith, a'diaphragm assembly comprising a relatively fixed and a relatively movable diaphragm, each provided with inner and outer free ends, the inner end of 'said relatively fixed diaphragm being seated in the indented portion in the free edge of said hollow support in bonded relation therewith, a head portion reduced at one end thereof to provide a shoulder, the inner end ofthe relativelymovable diaphragm being seated on the shoulder of said head portion in bonded relation therewith, the outer free ends of said diaphragms being turned back upon themselves in a direction toward said disk to provide an indented portion, said outer free ends of the diaphragms being bonded together at said indented portion, and said disk and diaphragm assembly limiting a fluid chamber.

JOHN E. WOODS. 

